1. Field of the Invention
This invention is directed to biocidal compositions containing a haloalkynyl compound, and especially a halopropargyl compound. The invention is specifically directed to compositions containing inclusion complexes of such halopropargyl compounds. In its preferred form, the present invention is directed to water soluble inclusion complexes of such halopropargyl compounds, especially those made water soluble by the use of a modified cyclodextrin.
2. Description of Related Art
Both exterior and interior surfaces and substrates of all types, when exposed to common environmental conditions, e.g., moisture, are prone to attack, discoloration and various kinds of destruction by a variety of species of microorganisms, including fungi, algae, bacteria and protozoa. The end result of such microbial attack is decomposition of the material, unsightly defacement or foul odors. In this respect microorganisms are a formidable enemy. They are basically found everywhere on the earth, in the water and in the air. They survive under diverse conditions such as in dust, nearly boiling water in hot springs and in salty water with a salt concentration of up to 30%, in light or darkness, and with small or large amounts of moisture and a wide range of nutrients. As a result, there is a great need and requirement for an effective and economical means to protect, for extended periods of time, both exterior and interior surfaces and various types of substrates and commercial formulations from the deterioration and destruction caused by such microorganisms.
Materials which need protection with a suitable antimicrobial composition include stucco, concrete, stone, cementaceous surfaces, iron, wood, caulking, sealants, leather, rope, paper pulp, plastics, textiles, biodegradable compositions including such materials as paints and other coating formulations, surfactants, proteins, starch-based compositions, stabilizers, inks, emulsifying agents, cellulose products, emulsions or suspensions, resins, shampoos, creams, lotions, cosmetics, soaps, and household products such as laundry detergents, hard surface cleaners, and fabric softeners, as well as numerous other materials and other substances which may be attacked by destructive microbes. Many of these applications would greatly benefit from an aqueous biocidal composition or they require a biocidal composition containing a large amount of water. For example, some of the above applications such as ink, sap stain, leather, textiles, surfactants, thickeners, metal working fluids, paper pulp, cellulose products, shampoos, creams, lotions, soaps, thickeners etc. consist of a large amount of water. For such applications, it is desirable to have a biocide which is water soluble for ease of incorporation, physical stability of the formulation and perhaps enhanced efficacy.
A wide variety of materials have been identified which, to various degrees, are effective in retarding or preventing the growth of, and accompanying destruction caused by such microbes. Such biocidal compounds include halogenated compounds, organometallic compounds, quaternary ammonium compounds, phenolics, metallic salts, heterocyclic amines, formaldehyde donors, organo-sulfur compounds and the like.
Formulated products that are protected against microbial attack by the inclusion of such biocidal additives must retain their biocidal activity for a prolonged time period to be most useful. Indeed, such products often are used to impart a biocidal activity to another product or to a substrate, such as wood and the like, which itself requires extended protection against microbial attack.
One well-known class of biocides are those containing a halopropargyl moiety, and especially an iodopropargyl moiety. Such compounds are widely disclosed in the patent literature including U.S. Pat. Nos. 3,660,499; 3,923,870; 4,259,350; 4,592,773; 4,616,004 and 4,639,460 to name a few. Included within this class of compounds are the halopropargyl carbamates which are known primarily for their fungicidal activity. 3-iodo-2-propynyl butyl carbamate, hereinafter also referred to as IPBC, is one of the best known and probably the most widely used of the halopropargyl carbamate fungicides. IPBC is a highly active broad spectrum fungicide. In addition to its fungicidal activity, IPBC also has been associated with algaecidal activity. In this regard, Great Britain Patent 2,138,292 and U.S. Pat. Nos. 4,915,909 and 5,082,722 contain such disclosures.
These compounds possess two reactive sites namely the carbon-carbon triple bond and the carbon-halogen, especially a carbon-iodine, bond. Depending on the pH of the system, nucleophiles, organic and inorganic acids and bases used in various applications can attack the halo(iodo)propargyl group, with gradual loss of the biocidal activity over time. Another kind of halo(iodo)propargyl instability is encountered in the dry film of coating compositions. The main cause of this decomposition mechanism is the exposure of the coating to shorter wavelengths of the electromagnetic spectrum of sunlight, namely ultraviolet radiation. This general phenomenon has been studied and documented by Gabriele et al., (U.S. Pat. No. 4,552,885). One approach taken by Gabriele et al to protect various biocides is to incorporate a combination of a piperidine compound and a UV absorber into the coating composition. Unfortunately, this approach has not heretofore been practical with the halo(iodo)propargyl compounds because the piperidine adjuvant used in conjunction with the UV absorbers destabilizes the halopropargyl compounds in the coating composition in aqueous formulations.
It is one object of the present invention, therefore, to provide a composition and method for stabilizing such halopropargyl, and especially iodopropargyl compounds, and most especially 3-iodo-2-propynyl butylcarbamate (IPBC), known in commerce as Troysan Polyphase.RTM., not only in an ultimately dry film but also in aqueous compositions such as a latex paint. In this regard, it is especially an object of the invention to provide a stability-enhancing inclusion complex of a halopropargyl compound and especially IPBC.
Most of the compounds belonging to the class of halopropargyl compounds, and especially the iodopropargyls such as IPBC, also have a limited water solubility i.e., 50-300 ppm and therefore, such compounds are often times difficult to incorporate in systems which have water as a predominant ingredient.
It is therefore another object of the present invention to provide a water soluble inclusion complex of a halopropargyl compound, especially 3-iodo-2-propynyl butylcarbamate (IPBC).